The present invention relates to a printer of the type in which thermally fusable ink is transferred from a transfer sheet to a record medium upon pressure contact with a thermal print head.
Conventional printers employ dither matrix technique whereby the tone value of each picture element is resolved into 16 discrete values and represented by a corresponding number of dots located in specified positions of a matrix of 4 rows and 4 columns. One disadvantage of this technique is the difficulty in increasing the number of resolution steps. This results in an image having no subtle differences in shades and nuances of the original.